Hello
Thanks for your query.
A
tubal ligation is not 100 % effective against
pregnancy, a very low failure rate does exist.
Also, ectopic pregnancy ( pregnancy outside the
uterus - in the tubes or ovaries ) is possible.
A pregnancy test should be positive by the first day of your missed period, but sometimes in late conception or ectopic pregnancy, amount of B
HCG is low, so test might give you falsely negative reading.
Please consult your gynecologist to diagnose the cause of your symptoms.
Sometimes, the problems you describe occur due to
hormonal disturbances after tubal ligation, the condition is called post tubal ligation syndrome.
For exact diagnosis, visit your gynecologist
Take care